Salvadoran troops shot and killed an Italian technician late last night when the pickup truck in which he was riding ran through an Army roadblock, an armed forces communique said late this evening.

The communique did not describe specifically how the shooting took place, and several details remained unclear.

The embalmer of the dead man said--and a brief viewing of the body confirmed--that he was hit by one bullet squarely in the middle of the chest. It was not clear whether he was shot while the pickup truck was racing away from the roadblock or after it stopped.

A Swiss colleague of the dead man was wounded in the incident, according to a Salvadoran colonel, although the communique did not mention the second casualty. The Swiss--Claude Bernard Levanchy, wounded in the leg--declined to discuss the incident when questioned by reporters in his hospital room.

The shootings took place on the Pan-American Highway at the Quebrada Seca bridge in San Vicente Province about 40 miles east of San Salvador. The incident showed that it still can be dangerous to travel at night on the main road in San Vicente, site of a major U.S.-backed program to establish military security and promote economic development.

Soldiers guarding the bridge may have been nervous late at night because of reports of guerrilla activity in the area. Left-wing insurgents killed more than 40 soldiers near the bridge in late May.

The armed forces communique, issued more than 19 hours after the shootings took place, said that "Italian citizen Vittorino Andretto was killed in the middle of the night on Tuesday the 23rd when the pickup vehicle in which he was riding accompanied by three other foreign technicians passed through a military roadblock at great speed . . . . Andretto died instantly as a consequence of bullets fired by armed forces personnel reponsible for guarding the bridge."

Andretto, 27, was employed by the Italian-Swiss engineering firm COGEFAR, which is helping the Salvadoran electrical utility CEL to build a dam.

Andretto was the 15th West European or U.S. citizen to be killed in recent years in El Salvador. Salvadoran security forces have been criticized for lack of discipline or charged with murder in several of the cases.

The communique stressed that the driver of the pickup had not halted when the roadblock guard signaled him to stop. A Defense Ministry communique said that Gen. Carlos Eugenio Vides Casanova, the defense minister, "regretted the tragic death" but stressed that ministry spokesmen "appealed to the citizenry to comply with the security rules issued by the Armed Forces to avoid sad situations like that of the foreign technician."